Create a btrfs backing dev info

This allows intelligent versions of unplug and congestion functions

Signed-off-by: Chris Mason <chris.mason@oracle.com>

3 files changed, 60 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f43dfe7ffe6d..fec96ba7c23b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -25,6 +25,7 @@
 #include <linux/fs.h>
 #include <linux/workqueue.h>
 #include <linux/completion.h>
+#include <linux/backing-dev.h>
 #include <asm/kmap_types.h>
 #include "bit-radix.h"
 #include "extent_io.h"
@@ -472,6 +473,7 @@ struct btrfs_fs_info {
         struct block_device *__bdev;
         struct super_block *sb;
         struct inode *btree_inode;
+        struct backing_dev_info bdi;
         spinlock_t hash_lock;
         struct mutex trans_mutex;
         struct mutex fs_mutex;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d8474796dea2..6a70e4916ab4 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -655,6 +655,55 @@ static int add_hasher(struct btrfs_fs_info *info, char *type) {
         return 0;
 }
 #endif
+
+static int btrfs_congested_fn(void *congested_data, int bdi_bits)
+{
+        struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
+        int ret = 0;
+        struct list_head *cur;
+        struct btrfs_device *device;
+        struct backing_dev_info *bdi;
+
+        list_for_each(cur, &info->fs_devices->devices) {
+                device = list_entry(cur, struct btrfs_device, dev_list);
+                bdi = blk_get_backing_dev_info(device->bdev);
+                if (bdi && bdi_congested(bdi, bdi_bits)) {
+                        ret = 1;
+                        break;
+                }
+        }
+        return ret;
+}
+
+void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
+{
+        struct list_head *cur;
+        struct btrfs_device *device;
+        struct btrfs_fs_info *info;
+
+        info = (struct btrfs_fs_info *)bdi->unplug_io_data;
+        list_for_each(cur, &info->fs_devices->devices) {
+                device = list_entry(cur, struct btrfs_device, dev_list);
+                bdi = blk_get_backing_dev_info(device->bdev);
+                if (bdi->unplug_io_fn) {
+                        bdi->unplug_io_fn(bdi, page);
+                }
+        }
+}
+
+static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
+{
+        bdi_init(bdi);
+        bdi->ra_pages   = default_backing_dev_info.ra_pages;
+        bdi->state              = 0;
+        bdi->capabilities       = default_backing_dev_info.capabilities;
+        bdi->unplug_io_fn       = btrfs_unplug_io_fn;
+        bdi->unplug_io_data     = info;
+        bdi->congested_fn       = btrfs_congested_fn;
+        bdi->congested_data     = info;
+        return 0;
+}
+
 struct btrfs_root *open_ctree(struct super_block *sb,
                               struct btrfs_fs_devices *fs_devices)
 {
@@ -708,11 +757,14 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         fs_info->max_extent = (u64)-1;
         fs_info->max_inline = 8192 * 1024;
         fs_info->delalloc_bytes = 0;
+        setup_bdi(fs_info, &fs_info->bdi);
         fs_info->btree_inode = new_inode(sb);
         fs_info->btree_inode->i_ino = 1;
         fs_info->btree_inode->i_nlink = 1;
         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
+        fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
+
         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
                              fs_info->btree_inode->i_mapping,
                              GFP_NOFS);
@@ -992,6 +1044,7 @@ int close_ctree(struct btrfs_root *root)
 #endif
         close_all_devices(fs_info);
         btrfs_mapping_tree_free(&fs_info->mapping_tree);
+        bdi_destroy(&fs_info->bdi);
 
         kfree(fs_info->extent_root);
         kfree(fs_info->tree_root);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index db60d85598ce..0fa7cf227f1a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -494,6 +494,7 @@ void btrfs_read_locked_inode(struct inode *inode)
         switch (inode->i_mode & S_IFMT) {
         case S_IFREG:
                 inode->i_mapping->a_ops = &btrfs_aops;
+                inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
                 inode->i_fop = &btrfs_file_operations;
                 inode->i_op = &btrfs_file_inode_operations;
@@ -508,6 +509,7 @@ void btrfs_read_locked_inode(struct inode *inode)
         case S_IFLNK:
                 inode->i_op = &btrfs_symlink_inode_operations;
                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
+                inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
                 break;
         default:
                 init_special_inode(inode, inode->i_mode, rdev);
@@ -1792,6 +1794,7 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
                 drop_inode = 1;
         else {
                 inode->i_mapping->a_ops = &btrfs_aops;
+                inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
                 inode->i_fop = &btrfs_file_operations;
                 inode->i_op = &btrfs_file_inode_operations;
                 extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
@@ -2960,6 +2963,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
                 drop_inode = 1;
         else {
                 inode->i_mapping->a_ops = &btrfs_aops;
+                inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
                 inode->i_fop = &btrfs_file_operations;
                 inode->i_op = &btrfs_file_inode_operations;
                 extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
@@ -2999,6 +3003,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 
         inode->i_op = &btrfs_symlink_inode_operations;
         inode->i_mapping->a_ops = &btrfs_symlink_aops;
+        inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
         inode->i_size = name_len - 1;
         err = btrfs_update_inode(trans, root, inode);
         if (err)